The overall goal of this project is to evaluate methods for detecting and characterizing genetic effects on common diseases and their risk factors by statistical genetic analysis of family and population data. This goal will be pursued by: (1) Continuing the organization of the Genetic Analysis Workshops (GAWs). For each GAW, topics are chosen that are relevant to current analytical problems in genetic epidemiology and sets of real or computer-simulated data are distributed to investigators worldwide. Results of analyses are discussed and compared at a two day meeting. GAW8 will be held in 1992 and GAW9 in 1994. Planning and data distribution for GAW10 will be underway by the end of the requested period of support in 1996. (2) Conducting evaluations of methods of genetic analysis. Some questions concerning the strengths and limitations of methods of genetic analysis cannot be properly addressed in a workshop setting, for example, questions of power, sensitivity, specificity, and robustness of various methods. Using computer-simulated data, the following issues would be addressed as they apply to analysis of quantitative traits: (a) detecting the effects of two or more loci on a trait; and (b) detecting and characterizing genetic effects in the presence of genotype by environment interaction. (3) Distributing simulation programs, simulated data, and programs for genetic analysis for use by other investigators. As a byproduct of our efforts in generating data for the GAWs and in evaluating methods of genetic analysis, a variety of computer programs and simulated data sets have been generated that are useful to other investigators. These programs and data sets will be documented and made available.